1. Field of the Invention
The present invention relates generally to the growth of diamond on a substrate seed crystal by chemical vapor deposition and more specifically to an apparatus and method for mounting a substrate seed crystal for the chemical vapor deposition of diamond.
2. Description of the Related Art
Most chemical vapor deposition processes for diamond growth occur at high temperatures of at least as high as 600.degree.-1600.degree. C. In the field of diamond growth by chemical vapor deposition, a diamond or a doped diamond substrate seed crystal is held within an oxygen-acetylene flame in order to promote the deposition of diamond on the substrate seed crystal in a hydrogen and hydrocarbon rich atmosphere. The temperature of the substrate seed crystal is regulated between 600.degree.-1600.degree. C.
To hold the substrate seed crystal within the flame, a brazing material is used to attach a substrate seed crystal to a mount. The mount is a rod to which the substrate seed crystal is attached by the use of a brazing material, which brazing material acts much like a glue between the rod and the substrate seed crystal.
There are two common problems with the use of a brazing material. The first problem is that the braze usually melts in the 900.degree.-1200.degree. C. range. The second problem is that the braze increases the possibility of contaminating the substrate seed crystal.
In addition, there is a common problem associated with the use of a conventional mount, a rod brazed to the substrate seed crystal. Typically, the substrate seed crystal temperature is difficult to control. The substrate seed crystal either tends to overheat or it is difficult to achieve the lower temperatures between 600.degree.-1250.degree. C. at the substrate seed crystal. The overall temperature of the substrate is poorly maintained. The lack of temperature control is due to a deficiency of thermal heat conduction carrying heat away from the mount rod and the attached substrate seed crystal.
From the problems discussed above, there is definitely a need for a better way to mount the substrate seed crystal on the mount rod and to control the substrate seed crystal temperature in the 600.degree.-1600.degree. C. range.